The present invention relates to processes and devices for determining the phase of the menstrual cycle and, particularly, to indicating the rheological properties of bodily mucus, particularly cervical mucus and/or oral mucus, in order to predict the inception and to indicate the presence of ovulation. The present invention thus is concerned with conception control. It has been found that mucus samples from the vaginal and oral cavities undergo distinct in-phase rheological changes during the menstrual cycle. Although the changes in the cervical mucus are much more noticeable than the changes in the oral mucus, both changes are readily determinable. During the immediate preovulatory phase, for a period of one to three days under estrogen domination, the mucus is profuse and watery. During the postovulatory phase, under progestation, the mucus becomes less abundant and more viscous. In healthy women with normal menstrual cycles, as is well documented in the medical literature, ovulation usually occurs between the 12th and 14th day prior to the next menstrual period (and not after the preceding period). Specifically, cervical mucus is most hydrated at the time of ovulation, containing 97 to 98% water, and is relatively dehydrated at other times, containing only 80 to 90% water. The solid residue after desiccation may range from 2% during ovulation to 20% at other times, a ten fold increase. Predicting ovulation on the basis of the preceding menstrual period by counting the number of days elapsed between the end of the preceding period and the presumed mid-cycle ovulatory phase (the rhythm method) is prone to errors because it is impossible to predict the onset of the next menstrual period. It is possible to predict ovulation on the basis of hormonal changes in the blood or chemical changes in the mucus but present procedures for such analyses are useful only in special cases because the procedures for such analyses are useful only in special cases because the procedures involved are lengthy and costly. At present, there are no known reliable on-the-spot techniques capable of providing the information necessary for prediction or confirmation of ovulation during or immediately following examination of a patient.